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Cleaning Titanium...

Discussion in 'The Garage' started by MikeO, Jul 16, 2007.

  1. MikeO

    MikeO Long timer Supporter

    Joined:
    Jul 27, 2002
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    17,143
    Location:
    Scarning, Norfolk today...
    I've got a titanium Z-Technik exhaust system on my 1150 Adventure...

    [​IMG]

    ...which, the more observant of you will have noticed, I have singularly failed to keep clean...

    [​IMG]

    In my own defence, I bought the system used (from Aurelius) and, having fitted a lowering kit, noticed that the clamp fitted in a different place with this kit in place. The mark left by this is just one of various marks over the length of the silencer.

    [​IMG]

    It also appears to have pitted - like the original BMW stainless steel silencer.

    [​IMG]

    So - the question is - how do I clean it? It isn't meant to have a polished finish, but rather a dull machined look. I'm not too concerned about the "Y-piece"...

    [​IMG]

    ...which is probably just as well... :lol3

    Any ideas?

    Mike :ear
    #1
  2. Stook

    Stook Who you callin' a n00b?

    Joined:
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    (pictures removed to simplify reply)
    Short answer: It won't be easy.
    Longer answer, good chance you are going to need a highly diluted acid solution followed by a rinse agent that will neutralise the acid (so it stops eating away at the titanium right about the time the dirty surface layer is consumed).

    Hopefully you will get better answers with easier solutions suggested. :)
    #2
  3. tbarstow

    tbarstow Two-wheelin' Fool Super Supporter

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    MikeO,

    I'll start with I am a Metallurgist and I work for a Titanium company.

    The yellow stuff is an oxide scale that forms when you get Ti to 1000°F. Acid doesn't remove this, its pretty much inert to everything. We sandblast it off our forgings.

    If you go that route, it may still have some discoloration, but should look OK.

    If you want it to look like new, you have to sandblast and pickel to remove the very hard surface condition called alpha-case. A do-it-yourself acid cleaner won't work, as it isn't strong enough to tear apart the Ti atoms from everything they are bonded with.

    The next step would be to take it to a professional pickling shop that will use a combination of hydrofluoric acid and hydrochloric acid to remove what is left. Just tell them how much you want removed (usually .010" is sufficient). Once the alpha-case is removed, it will have the bright gray surface again.

    Then just don't get it hot again.

    I'd stick with the sandblasted finish.
    #3
  4. krampus

    krampus get lost

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    I'll start with I'm a bonehead weekend wrench...plus, you're reading this on the internet, so you know it must be true. Try Simple Green "Automotive" as a loob + fine steel wool "00" or finer and a bunch of good ol' fashioned elbow grease. Might not be perfect, but it'll prolly turn out nicer than you thought. The only caveat I know is that Ti can be brittle...others more informed than I should chime in.
    #4
  5. GSWayne

    GSWayne Old Guy nOOb Supporter

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    Thanks for the professional advice, but I have a one question.

    Do you really mean .010"? Isn't that about a third of the thickness of the muffler material? I haven't measured the thickness of one, but I would think it would be pretty thin.
    #5
  6. Poolside

    Poolside Syndicated

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    <BR>
    Did you hear the part about don't get the titanium hot again? He (tbarstow) means that the oxidization process begins again and ends up right where you started.

    Maybe try some 220 grit metal sandpaper once in a while and create a directional brushed finish.
    <BR><BR>
    #6
  7. tbarstow

    tbarstow Two-wheelin' Fool Super Supporter

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    I don't know how thick they are, but I'll check the thickness of the stuff we sell to Akropovic. I'd sand blast it and leave it alone.

    But really, its a GS, its SUPPOSED to be dirty!
    #7
  8. MikeO

    MikeO Long timer Supporter

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    Many thanks for all the replies.

    I started off by spending an hour or so with an old T-shirt and a can of WD-40...

    [​IMG]

    The silencer came up remarkably well.

    [​IMG]

    ...and the Y-pipes are as good now as when I bought them.

    The only problem areas are where the clamp fits...

    [​IMG]

    Aurelius fitted the exhaust in its normal position, I fitted it with a lowering kit. The rubber (butyl?) lined clamp has marked the surface in the two different areas it fitted.

    [​IMG]

    The marks seem to be scuffs on the surface of the metal where the pipe has moved fractionally and repeatedly over many miles. I don't think there is any way to get rid of them without doing something extreme like wire-brushing or sand/bead blasting the whole can.

    Does anybody have any other ideas?

    Cheers,

    Mike :ear
    #8
  9. Mr Head

    Mr Head Adventure Hippie Supporter

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    Looks good.

    You know with the bags on the bike you can't see the pipe...
    #9
  10. MikeO

    MikeO Long timer Supporter

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    Yes - that's the tactic I've been using - but now I want to sell the system...

    Mike :)
    #10
  11. SnowFarmer

    SnowFarmer Adventurer

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    I have a lot of Titanium for my motocross bike. S100 works wonders.
    The metallurgist could tell you more about it, I got the idea from Factory Honda (they use Hondabrite) which is re branded S100.

    Mind you this stuff is caustic to aluminum. But we soak bolts in the stuff and they come out looking brand new.
    #11
  12. MikeO

    MikeO Long timer Supporter

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    As far as I can see from their website, S100 is a cleaner. I'm pretty happy that the system is about as clean as it's going to get - the marks I 'd like to remove are scuffs on the surface of the can...

    Mike :)
    #12